This project involved the installation of a temporary sandbag weir in an artificial drain on a private property near Portland, in far south-western Victoria. The temporary weir was constructed using sandbags made from geo-textile material placed to form a weir wall and overflow sill within the existing drainage channel. The trial sandbag structure is designed to function as a drainage regulation weir, where water flowing out of the drainage channel is retained to promote pooling of the backwater into the natural wetland depression located directly upstream. In this instance, the landholder was interested in restoring the natural wetland area – noting that this area had become much drier since the construction of the drain – as the wetland area itself was considered to be of marginal value for agricultural purposes.
The temporary sandbag weir was installed in early June, prior to the above average July rains in that district, being completed by the landholder, members from a local landcare group and Nature Glenelg Trust. The weir structure has been designed to recreate a 4 hectare wetland area by restricting drainage outflows by up to 60 cm within the existing drainage channel. NGT’s Lachlan Farrington put together a short summary of the action, which can be viewed below: